Many thanks PhotoEcosse and Dave about your recommendations...
Yes, I know it is going to be hard to be out the best hours in terms of light... That it is one of the reasons I don't want to be moving around a lot, so I make a base for three days in one place and I can get some decent hours of sleep during daytime... It is going to be tough, but I'm sure I will enjoy it ;-).
Also, about the weather, although I have been living in Barcelona for the last two years, I'm from Santiago de Compostela in the Galicia country in Spain, 90% of the time it is raining, so I'm used to the bad weather, and I'm the kind of person that tries until last second to see if the conditions break and get better to take a photograph, many of my best photographs were done like this... bad weather a lot of times means great photographs.
About your national drink, I have to buy a bottle of that as a present for a friend of mine, another friend told me to go to Dagda pub at Edinburgh to try different kinds of that national drink. I don't exactly which kind likes my friend, I will make sure that at least I like the drink, so in case my friend does not like it, more for me!!!
Thanks again, now I have to redefine my plan... I will probably miss a lot of places, but I'm quite sure this is not going to be my last trip to Scotland!!!